Indexing of Iranian Publications in Well-known Endodontic Textbooks: A Scientometric Analysis

Introduction: Quoting an article in well-known textbooks is held as a credit for that paper. The numbers of Iranian publications mentioned in endodontic textbooks have increased during recent years. The aim of this investigation was to evaluate the number of Iranian articles quoted in eminent endodontic textbooks. Methods and Materials: Three known textbooks (Ingle’s Endodontics, Seltzer and Bender’s Dental Pulp and Cohen’s Pathways of the Pulp) were chosen and all the editions of the textbooks since 2000 were investigated for quoted Iranian publications. Only Iranian authors with affiliations from a domestic university were chosen. All references at the end of each chapter were read by hand searching, and results were noted. The trend and percentage of Iranian publications in different editions of the textbooks were also calculated. The number of citations of these publications in Google Scholar and Scopus databases were also obtained. Results: The number of Iranian publications in all well-known textbooks have notably increased since 2000. The number and percentage of Iranian publications in the latest edition of Cohen’s Pathways of the Pulp was higher compared to other textbooks as well as the previous edition of the same text. Conclusion: Number and percentage of Iranian publications in the field of endodontics in all three textbooks have remarkably increased since 2000.


Introduction
ne of the most important aims of publishing scientific articles is to provide a reliable source of information for readers. Although performing laboratory and animal studies is necessary to provide basic information regarding the efficacy and safety of dental materials and techniques, nowadays the most leading dental journal are emphasizing on evidence-based investigations in order to provide reliable results for clinical practice [1,2].
Textbooks are important documents in scientific field. Text book contributors are usually among well-known high reputation scientists and for that reason the chapters that have been prepared by them would be a reliable source for the readers. Therefore, quoting an article in a text book is assumed to be held as a credit for the authors. It has been reported that the science production in dentistry has faced a 5.68% growth from 2000 to 2009 [3]. Because of the encouraging policy of national universities, Iranian researchers prefer to publish their papers in international English journals. Therefore, there is a tendency to increase international publications of the Iranian endodontists.
Endodontics is one of the well-organized fields of dentistry in Iran. Iranian Association of Endodontics (IAE) is a nongovernmental association that has been founded since 1995. Apart from holding annual congresses since 1997, IAE is the holder of Iranian Endodontic Journal (IEJ) which has been publishing endodontic papers since 2006. IEJ is indexed in a number of data bases including Scopus and PubMed.
Scientific authority is an important issue for both Iranian universities and IAE. The aim of the present study is to evaluate the trend of appearance of the publications from Iranian authors in well-known endodontic textbooks.

Materials and Methods
Three textbooks which are references for Iranian board certificate (including Ingle's Endodontics, Seltzer and Bender's Dental Pulp and Cohen's Pathways of the Pulp) were chosen to be evaluated (Table 1). In addition, in order to evaluate the trend of Iranian endodontists quotes in these books, all editions of the books since 2000 had been evaluated. The reference part of all chapters of these books had been evaluated through hand searching by two independent reviewers. All Iranian names had been collected and then reviewed by the third reviewer. Only the articles that their first author was Iranian with domestic affiliation were chosen. By using Google Scholar, PubMed and Scopus data bases, the affiliation and the number of each cited articles were extracted. If a paper was cited several times in the same text book, only one quote was taken into account. University of the authors was also considered. The percentage of Iranian endodontists quotes in each text book was calculated by dividing the number of the Iranian papers by the total number of references that appeared in those books.

Results
A total of 64 papers have been found in separate versions of the textbooks . Since 2000, Cohen's Pathways of the Pulp was reprinted 4 times, whereas Ingle's endodontics and Bender and Seltzer's Dental Pulp had been reprinted twice within the same time period. Table 2 shows the number of the Iranian papers cited in consecutive publications in different editions of the textbooks. Figure 1 shows the trend of Iranian authors' publications that were cited in different textbooks. The type of quoted papers in descending order was randomized-controlled clinical trials, in vitro studies and review papers (Table 3). Several investigations have been quoted in different editions of the textbooks ( Table 4). The trend of publications in Cohen's Pathways of the Pulp showed that the number of citations has increased from 0.003 to 0.62 in 2016. Figures 2 to 4 show that articles published by endodontic departments of some universities' had been more quoted.

Discussion
The results of the present study showed that the citation of the articles that had been written by Iranian authors in well-known textbooks have notably increased during recent years. In the

Figure 2. Universities that their publications had been cited in Seltzer and
Bender's Dental Pulp present study, three well known textbooks (Table 1) were used to evaluate the scientific authority of Iranian endodontists because these books were chosen as the reference books of postgraduate programs in Iran [67]. In this study, only the papers with their first author being affiliated from one of the domestic universities were chosen, because previous investigations in sicentometric field also considered this criterion [68]. The trend of Iranian authors' publications that were quoted in these textbooks was particularly promoted in the recent 11 th  (Tables 1 and 2).
Most Iranian authors' papers that were quoted in the latest edition of Cohen's Pathways of the Pulp were randomized clinical trials followed by in vitro and review papers (Table 3). Nowadays, high level of evidence investigations are being encouraged to be performed because of their high reliability for clinical practice [1,2].     The percentage of the Iranian authors' papers that were quoted in Ingle's endodontics were lower compared to the two other textbooks. The reason of this difference may be the year of publication of these books because the latest publication of Ingle's endodontics was in 2008, whereas the latest publication year of the Cohen's Pathways of the Pulp and Bender and Seltzer's Dental Pulp is 2016 and 2012, respectively. The number of published papers from Iranian authors in the field of endodontics has increased in recent years [69,70].

Conclusion
The current study shows positive trend of Iranian endodontic articles quoted in three endodontic textbooks.